Jacketed Valves

CSI Valve Jackets

Valves can be jacketed with a fabricated (weld-on) jacket or a ControHeat® bolt-on jacket.

Since 1970, CSI has been fabricating weld-on jackets for all types of valves. We design, fabricate, and test our valve jackets in accordance with the ASME Boiler and Pressure Vessel Code, Section VIII, Division 1. All valves are pressure and leak tested before and after jacketing. There are numerous jacketing considerations, including flange size, full or partial coverage, types and locations of heating medium connections, bonnet jackets or additional heat coverage for specific areas, and materials of construction. Before specifying fabricated jacketed valves, designers should carefully consider the thermal requirements of the process along with the flange sizes and valve types to be used. For example, most large, full-port ball valves are available only in two- or three-piece configurations. Fabricating full jackets on these types of valves can be very expensive. Metal-seated ball and plug valves are also difficult to jacket without compromising leak-rate standards. In these instances, designers may be better served to consider ControHeat® bolt-on heating jackets.

There are four basic categories of CSI fabricated jacketed valves:

Type A: Partial Jacket, Core-Size Flanges.

The original valve body is maintained. The jacket terminates a short distance from the back of the flange. Type A jacketed valves are used with swaged and non-reducing insert-flanged jacketed piping where broad process temperature ranges are acceptable.

Type B: Full Jacket, Jacket-Size Flanges.

The valve body is lengthened, and the flanges are replaced with oversize flanges. The jacket covers the body of the valve and extends flange to flange, terminating at the back of the oversize flange. The new face-to-face dimension is the same as a standard valve of size equal to the flange size. For example, a Type B 3-in. X 4-in. jacketed plug valve has the face-to-face dimension of a 4-in. plug valve. Type B jacketed valves are used with standard and reducing insert-flanged jacketed piping.

Type C: Full Jacket, Core-Size Flanges.

The original valve body is maintained, and the valve flange bolt holes are modified with tapped inserts. The jacket covers the body of the valve and extends flange to flange, terminating on the periphery of the flanges. Type C jacketed valves must be installed by inserting and threading studs from the adjacent mating flanges. The tapped inserts are double-seal welded on front and back to contain the heating fluid. Type C jacketed valves are used with swaged and non-reducing insert-flanged jacketed piping.

Type D: Full Jacket, Jacket-Size Flanges, Short Body.

The valve flanges are replaced with oversize flanges. The jacket covers the body of the valve and extends flange to flange, terminating at the back of the oversize flange. The face-to-face dimension is the same as a standard valve of size equal to the body size. For example, a Type D 3-in. X 4-in. jacketed globe-type control valve has the face-to-face dimension of a 3-in. globe-type control valve. Type D jacketed valves are used with standard and reducing insert-flanged jacketed piping, usually in very dense piping systems where space is limited.